Internal combustion engine piston



July 6, 194:3.

P. s. WEBSTER INTERNAL COMBUSTION ENGINE PISTON Filed March 19 1942 2 Sheets-Sheet l WXness vJ/f.

3mm Phi/()0 6'. Wesie r y 1943- P. s. WEBSTER 2,323,742

INTERNAL G OMBUS T I ON ENGINE P I S TON 2 Sheets-Sheet 2.

Filed March 19 1942 21am; 6. Webster .to provide such a Panel July e, 1943 NITED STATES PATENT orrics fiiifilflffiff -4 Claims. (Cl. 309-15) The present invention relates to an internal combustion engine piston and more particularly to a flexible piston for use in such an engine.

The primary'objects of the instant invention are to provide a piston of the general character above indicated which is particularly well adapted for use in motors operated by low grade fuels;

piston whereby the thermodynamic efliciency of the motor is increased; to provide such a piston whereby a constant maximum combustion pressure is maintained during varying speed and load conditions of the working stroke of the piston and a more complete scavenging action is effected during its exhaust stroke; to provide such a piston wherein relatively little heat is transferre from the combustion head of the piston to its piston pin; to provide such a piston'wherein a free circulation of air and head of the piston and its piston pin ,is permitted; to provide such a piston wherein its combustion head remains concentric with its cylinder wall at all times, dissipating its heat unis formly to the piston rings, thereby maintaining a better seal and a minimum amount of blow-by; to'provide such a piston wherein there is no piston ring scoring of the cylinder wall frequently resulting in other types of pistons in instances wherein a piston slap develops as the result of a freezing action of the piston pin;.to provide detonation is prevented such a piston wherein but otherwise results in instances wherein the gas fails to expand when the critical pressure of the fuel used is reached; to provide such a piston whose use in an internal combustion engine makes for more economical operation; to provide such a piston-whose use permits of rela-' tively higher compression ratios than are pos.

sibie in instances of other type internal combustion engines using standard grade fuels; and, to provide such a piston which is reasonably light in weight, highly eiiicient in use and is economical in manufacture.

An illustrative embodiment of the invention is shown in the accompanying drawings, wherein: Figure 1 is a vertical central sectional view of the piston on lines l-l of Figures 2 and 4;

' Figure 2 isa fragmentary top plan view there- Figure 3 is a side elevational view; Figure 4 is a sectional view on Figure 3;

Figure 5 is a vertical central sectional on line 5-5 of Figure 3;

line H of view Figure 6 is a sectional view thereof on line 8-8 of Figure 5;

Figure 'l is a sectional view on line 1-1 of Figure 5; and

Figure 8 is a perspective view of the member which secures the flexible piston head to its piston pin carrying base.

Referring then parts of the structure shown are each designated by the same numerals in the several views, the vertically flexible or axially expansible-contractible piston there shown generally comprises an upper portion or combustion hea It), a lower portion ll carrying a wrist pin l2, a central connecting member l3 for securing the upper portion ill to the lower portion ii and a helical expansion spring ll interposed between the upper portion of the piston and the lower portion thereof. 7 1

The upper portion iii of the piston is provided with a pair of spaced horizontally disposed opwhich shelves are each provided with a trans 'versely disposed slot i1, i8 and bolt shank IS on which a nut 20 is adapted to be screw threadedly secured, centrally depends from the interior of the upper portion of the piston, all as best shown in Figures 1, 5 and 6.

The upper portion ID of the piston is provided with conventional compression and oil ring grooves 2i 22 respectively, the latter of which are each provided with oil ports 23 and the lower end of the upper portion of the piston has a depending hub 24 for centering the upper end of the helical expansion spring ll when the several parts of the piston are secured together in their assembled relation.

The upper ,end piston is provided with an upstanding hub 25 for centering the lower end of the helical expansion spring I! when the several parts are secured together in their assembled relation and a lower portion of the piston ispreferably further provided with a plurality of vertically disposed oil draining ports 26.

The head 21 of the central connecting member I3 is provided with a bolt shank receiving aperture and the lower oppositely disposed sides 2!, I. are generally flared outwardly-downwardly and abut oppositely disposed shoulders 8|, 32 interiorly of the lower end of the lower portion Iiv to the drawings wherein like a screw threaded of the lower portion Ii of the combustion pressure on the upper surface of upper portion of the piston and a plate 35 secured to the head 21 of the central connecting member as by spot welding and seated in the oppositely disposed slots l1, 18 of horizontally spaced shelves l5, I6 is provided with a bolt shank receiving aperture through which the bolt shank I9 is passed for securing the several parts of the piston together in the manner now to be described.

In securing the several parts of the piston in their assembled relation, the central connecting member I 3 is first slid upwardly through the lower portion ll of the piston until its oppositely disposed flared sides 29, 30 abut its oppositely disposed shoulders 3|, 32.

The hub of the connecting rod, not shown, is next slid upwardly into the lower portion ll of the piston and the wrist pin I2 is then passed therethrough andthrough the aligned oppositely disposed wrist pin slots 33, 34 after which the lower end of the helical expansion spring I 4 is centered upon the upstanding hub 25-01 the lower portion ll of the piston.

The depending hub 24 of the upper portion ill of the piston is next placed within the encircling upper portion of the helical expansion spring l4 which is thereupon compressed and the plate 35 secured to the head 21 of the central connecting member I3 is rotated from its position shown in dotted lines in Figure 6 to its position shown in full llnes'in the same view,'seating the opposite ends thereof within the transversely disposed slots l1, l8 of the oppositely disposed shelves l5, I6 whereupon the lock nut is threadedly secured to the bolt shank 19 to provide a rigid connection between the central connecting member l3 and the upper portion III of the piston under all operating conditions.

Combustion of the atomized fuel within the cylinder and above the head of the upper portion In of the piston, causes the upper end thereof to travel downwardly and any excessive combustion pressure on the head is taken up through the helical expansion spring l3 with no loss of power since the upper portion ill of the piston will resume its normal position before the end of the power stroke, thereby preventing detonation and providing relatively higher compression ratios than are provided with conventional type pistons using standard grades of fuel.

Detonation which is caused by the sudden ignition of a charge of carbureted fu'el within the cylinder during the sweeping of the flame across the combustion chamber, is precluded in the instant invention since pressure within the cylinder is not built up therein because of its expanding combustion chamber. Thus the carbureted fuel burns gradually when ignited, resulting in complete pombustion and the maximum utilization of the available energy.

It will thus be seen that the flexible piston herein shown and described is reasonably light in weight, highly eflicient in use and is reasonably economical in manufacture and while but one specific embodiment of the invention has been herein shown and described, it will be understood that certain details of the construction shown may be alteredor omitted without departing from the spirit of the invention as the same is defined by the following claims.

I claim:

1. A piston for an internal combustion engine having an upper portion and a lower portion in spaced relation thereto having vertically spaced side walls whose lower ends are each provided with a shoulder, a connecting member secured to the upper portion of the piston and limitedly slidably disposed within the lower portion thereof whose lower ends are flared outwardly and are adapted toengage said shoulders, and a hellcal expansion spring interposed between the upper and lower portions of the piston.

A piston for an internal combustion engine having a hollow head portion and a lower portion in spaced relation thereto, the inner wall of said hollow head portion having a pair of spaced shelves, each provided with a transverse slot, a connecting member limitedly slidably disposed relative to the lower portion and having a head portion seated within said slots, and a helical expansion-spring interposed between the hollow head portion and the lower portion of the piston.

3. A piston for an internal combustion engine having an upper portion and a lower portion in spaced relation thereto having vertically spaced side walls whose lower ends are each provided with a shoulder, a connecting member secured to the upper portion of the piston and limitedly slidably disposed within the lower portion thereof whose lower ends are flared outwardly and are adapted to engage said shoulders, and a helical expansion spring interposed between the upper and lower portions of the piston and encircling the limitedly slidably disposed member.

4. A piston for an internal combustion engine having a hollow head portion and a lower portion in spaced relation thereto, the inner wall of said hollow head portion having a pair of spaced shelves, each provided with a transverse slot, a connecting member limite'dly slidably disposed relative to the lower portion and having a head portion seated within said slots, and a hellcal expansion spring interposed between the hollow head portion and the lower portion of the piston and encircling the limitedly slidably disposed member.

PHILIP S. WEBSTER. 

